// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.

#include "leveldb/c.h"

#include <stdlib.h>
#include "leveldb/cache.h"
#include "leveldb/comparator.h"
#include "leveldb/db.h"
#include "leveldb/env.h"
#include "leveldb/filter_policy.h"
#include "leveldb/iterator.h"
#include "leveldb/options.h"
#include "leveldb/status.h"
#include "leveldb/write_batch.h"

using leveldb::Cache;
using leveldb::Comparator;
using leveldb::CompressionType;
using leveldb::DB;
using leveldb::Env;
using leveldb::FileLock;
using leveldb::FilterPolicy;
using leveldb::Iterator;
using leveldb::kMajorVersion;
using leveldb::kMinorVersion;
using leveldb::Logger;
using leveldb::NewBloomFilterPolicy;
using leveldb::NewLRUCache;
using leveldb::Options;
using leveldb::RandomAccessFile;
using leveldb::Range;
using leveldb::ReadOptions;
using leveldb::SequentialFile;
using leveldb::Slice;
using leveldb::Snapshot;
using leveldb::Status;
using leveldb::WritableFile;
using leveldb::WriteBatch;
using leveldb::WriteOptions;

extern "C" {

struct leveldb_t {
    DB *rep;
};
struct leveldb_iterator_t {
    Iterator *rep;
};
struct leveldb_writebatch_t {
    WriteBatch rep;
};
struct leveldb_snapshot_t {
    const Snapshot *rep;
};
struct leveldb_readoptions_t {
    ReadOptions rep;
};
struct leveldb_writeoptions_t {
    WriteOptions rep;
};
struct leveldb_options_t {
    Options rep;
};
struct leveldb_cache_t {
    Cache *rep;
};
struct leveldb_seqfile_t {
    SequentialFile *rep;
};
struct leveldb_randomfile_t {
    RandomAccessFile *rep;
};
struct leveldb_writablefile_t {
    WritableFile *rep;
};
struct leveldb_logger_t {
    Logger *rep;
};
struct leveldb_filelock_t {
    FileLock *rep;
};

struct leveldb_comparator_t : public Comparator {
    void *state_;

    void (*destructor_)(void *);

    int (*compare_)(
            void *,
            const char *a, size_t alen,
            const char *b, size_t blen);

    const char *(*name_)(void *);

    virtual ~leveldb_comparator_t() {
        (*destructor_)(state_);
    }

    virtual int Compare(const Slice &a, const Slice &b) const {
        return (*compare_)(state_, a.data(), a.size(), b.data(), b.size());
    }

    virtual const char *Name() const {
        return (*name_)(state_);
    }

    // No-ops since the C binding does not support key shortening methods.
    virtual void FindShortestSeparator(std::string *, const Slice &) const {}

    virtual void FindShortSuccessor(std::string *key) const {}
};

struct leveldb_filterpolicy_t : public FilterPolicy {
    void *state_;

    void (*destructor_)(void *);

    const char *(*name_)(void *);

    char *(*create_)(
            void *,
            const char *const *key_array, const size_t *key_length_array,
            int num_keys,
            size_t *filter_length);

    unsigned char (*key_match_)(
            void *,
            const char *key, size_t length,
            const char *filter, size_t filter_length);

    virtual ~leveldb_filterpolicy_t() {
        (*destructor_)(state_);
    }

    virtual const char *Name() const {
        return (*name_)(state_);
    }

    virtual void CreateFilter(const Slice *keys, int n, std::string *dst) const {
        std::vector<const char *> key_pointers(n);
        std::vector<size_t> key_sizes(n);
        for (int i = 0; i < n; i++) {
            key_pointers[i] = keys[i].data();
            key_sizes[i] = keys[i].size();
        }
        size_t len;
        char *filter = (*create_)(state_, &key_pointers[0], &key_sizes[0], n, &len);
        dst->append(filter, len);
        free(filter);
    }

    virtual bool KeyMayMatch(const Slice &key, const Slice &filter) const {
        return (*key_match_)(state_, key.data(), key.size(),
                             filter.data(), filter.size());
    }
};

struct leveldb_env_t {
    Env *rep;
    bool is_default;
};

static bool SaveError(char **errptr, const Status &s) {
    assert(errptr != nullptr);
    if (s.ok()) {
        return false;
    } else if (*errptr == nullptr) {
        *errptr = strdup(s.ToString().c_str());
    } else {
        // TODO(sanjay): Merge with existing error?
        free(*errptr);
        *errptr = strdup(s.ToString().c_str());
    }
    return true;
}

static char *CopyString(const std::string &str) {
    char *result = reinterpret_cast<char *>(malloc(sizeof(char) * str.size()));
    memcpy(result, str.data(), sizeof(char) * str.size());
    return result;
}

leveldb_t *leveldb_open(
        const leveldb_options_t *options,
        const char *name,
        char **errptr) {
    DB *db;
    if (SaveError(errptr, DB::Open(options->rep, std::string(name), &db))) {
        return nullptr;
    }
    leveldb_t *result = new leveldb_t;
    result->rep = db;
    return result;
}

void leveldb_close(leveldb_t *db) {
    delete db->rep;
    delete db;
}

void leveldb_put(
        leveldb_t *db,
        const leveldb_writeoptions_t *options,
        const char *key, size_t keylen,
        const char *val, size_t vallen,
        char **errptr) {
    SaveError(errptr,
              db->rep->Put(options->rep, Slice(key, keylen), Slice(val, vallen)));
}

void leveldb_delete(
        leveldb_t *db,
        const leveldb_writeoptions_t *options,
        const char *key, size_t keylen,
        char **errptr) {
    SaveError(errptr, db->rep->Delete(options->rep, Slice(key, keylen)));
}


void leveldb_write(
        leveldb_t *db,
        const leveldb_writeoptions_t *options,
        leveldb_writebatch_t *batch,
        char **errptr) {
    SaveError(errptr, db->rep->Write(options->rep, &batch->rep));
}

char *leveldb_get(
        leveldb_t *db,
        const leveldb_readoptions_t *options,
        const char *key, size_t keylen,
        size_t *vallen,
        char **errptr) {
    char *result = nullptr;
    std::string tmp;
    Status s = db->rep->Get(options->rep, Slice(key, keylen), &tmp);
    if (s.ok()) {
        *vallen = tmp.size();
        result = CopyString(tmp);
    } else {
        *vallen = 0;
        if (!s.IsNotFound()) {
            SaveError(errptr, s);
        }
    }
    return result;
}

leveldb_iterator_t *leveldb_create_iterator(
        leveldb_t *db,
        const leveldb_readoptions_t *options) {
    leveldb_iterator_t *result = new leveldb_iterator_t;
    result->rep = db->rep->NewIterator(options->rep);
    return result;
}

const leveldb_snapshot_t *leveldb_create_snapshot(
        leveldb_t *db) {
    leveldb_snapshot_t *result = new leveldb_snapshot_t;
    result->rep = db->rep->GetSnapshot();
    return result;
}

void leveldb_release_snapshot(
        leveldb_t *db,
        const leveldb_snapshot_t *snapshot) {
    db->rep->ReleaseSnapshot(snapshot->rep);
    delete snapshot;
}

char *leveldb_property_value(
        leveldb_t *db,
        const char *propname) {
    std::string tmp;
    if (db->rep->GetProperty(Slice(propname), &tmp)) {
        // We use strdup() since we expect human readable output.
        return strdup(tmp.c_str());
    } else {
        return nullptr;
    }
}

void leveldb_approximate_sizes(
        leveldb_t *db,
        int num_ranges,
        const char *const *range_start_key, const size_t *range_start_key_len,
        const char *const *range_limit_key, const size_t *range_limit_key_len,
        uint64_t *sizes) {
    Range *ranges = new Range[num_ranges];
    for (int i = 0; i < num_ranges; i++) {
        ranges[i].start = Slice(range_start_key[i], range_start_key_len[i]);
        ranges[i].limit = Slice(range_limit_key[i], range_limit_key_len[i]);
    }
    db->rep->GetApproximateSizes(ranges, num_ranges, sizes);
    delete[] ranges;
}

void leveldb_compact_range(
        leveldb_t *db,
        const char *start_key, size_t start_key_len,
        const char *limit_key, size_t limit_key_len) {
    Slice a, b;
    db->rep->CompactRange(
            // Pass null Slice if corresponding "const char*" is null
            (start_key ? (a = Slice(start_key, start_key_len), &a) : nullptr),
            (limit_key ? (b = Slice(limit_key, limit_key_len), &b) : nullptr));
}

void leveldb_destroy_db(
        const leveldb_options_t *options,
        const char *name,
        char **errptr) {
    SaveError(errptr, DestroyDB(name, options->rep));
}

void leveldb_repair_db(
        const leveldb_options_t *options,
        const char *name,
        char **errptr) {
    SaveError(errptr, RepairDB(name, options->rep));
}

void leveldb_iter_destroy(leveldb_iterator_t *iter) {
    delete iter->rep;
    delete iter;
}

unsigned char leveldb_iter_valid(const leveldb_iterator_t *iter) {
    return iter->rep->Valid();
}

void leveldb_iter_seek_to_first(leveldb_iterator_t *iter) {
    iter->rep->SeekToFirst();
}

void leveldb_iter_seek_to_last(leveldb_iterator_t *iter) {
    iter->rep->SeekToLast();
}

void leveldb_iter_seek(leveldb_iterator_t *iter, const char *k, size_t klen) {
    iter->rep->Seek(Slice(k, klen));
}

void leveldb_iter_next(leveldb_iterator_t *iter) {
    iter->rep->Next();
}

void leveldb_iter_prev(leveldb_iterator_t *iter) {
    iter->rep->Prev();
}

const char *leveldb_iter_key(const leveldb_iterator_t *iter, size_t *klen) {
    Slice s = iter->rep->key();
    *klen = s.size();
    return s.data();
}

const char *leveldb_iter_value(const leveldb_iterator_t *iter, size_t *vlen) {
    Slice s = iter->rep->value();
    *vlen = s.size();
    return s.data();
}

void leveldb_iter_get_error(const leveldb_iterator_t *iter, char **errptr) {
    SaveError(errptr, iter->rep->status());
}

leveldb_writebatch_t *leveldb_writebatch_create() {
    return new leveldb_writebatch_t;
}

void leveldb_writebatch_destroy(leveldb_writebatch_t *b) {
    delete b;
}

void leveldb_writebatch_clear(leveldb_writebatch_t *b) {
    b->rep.Clear();
}

void leveldb_writebatch_put(
        leveldb_writebatch_t *b,
        const char *key, size_t klen,
        const char *val, size_t vlen) {
    b->rep.Put(Slice(key, klen), Slice(val, vlen));
}

void leveldb_writebatch_delete(
        leveldb_writebatch_t *b,
        const char *key, size_t klen) {
    b->rep.Delete(Slice(key, klen));
}

void leveldb_writebatch_iterate(
        const leveldb_writebatch_t *b,
        void *state,
        void (*put)(void *, const char *k, size_t klen, const char *v, size_t vlen),
        void (*deleted)(void *, const char *k, size_t klen)) {
    class H : public WriteBatch::Handler {
    public:
        void *state_;

        void (*put_)(void *, const char *k, size_t klen, const char *v, size_t vlen);

        void (*deleted_)(void *, const char *k, size_t klen);

        virtual void Put(const Slice &key, const Slice &value) {
            (*put_)(state_, key.data(), key.size(), value.data(), value.size());
        }

        virtual void Delete(const Slice &key) {
            (*deleted_)(state_, key.data(), key.size());
        }
    };
    H handler;
    handler.state_ = state;
    handler.put_ = put;
    handler.deleted_ = deleted;
    b->rep.Iterate(&handler);
}

void leveldb_writebatch_append(leveldb_writebatch_t *destination,
                               const leveldb_writebatch_t *source) {
    destination->rep.Append(source->rep);
}

leveldb_options_t *leveldb_options_create() {
    return new leveldb_options_t;
}

void leveldb_options_destroy(leveldb_options_t *options) {
    delete options;
}

void leveldb_options_set_comparator(
        leveldb_options_t *opt,
        leveldb_comparator_t *cmp) {
    opt->rep.comparator = cmp;
}

void leveldb_options_set_filter_policy(
        leveldb_options_t *opt,
        leveldb_filterpolicy_t *policy) {
    opt->rep.filter_policy = policy;
}

void leveldb_options_set_create_if_missing(
        leveldb_options_t *opt, unsigned char v) {
    opt->rep.create_if_missing = v;
}

void leveldb_options_set_error_if_exists(
        leveldb_options_t *opt, unsigned char v) {
    opt->rep.error_if_exists = v;
}

void leveldb_options_set_paranoid_checks(
        leveldb_options_t *opt, unsigned char v) {
    opt->rep.paranoid_checks = v;
}

void leveldb_options_set_env(leveldb_options_t *opt, leveldb_env_t *env) {
    opt->rep.env = (env ? env->rep : nullptr);
}

void leveldb_options_set_info_log(leveldb_options_t *opt, leveldb_logger_t *l) {
    opt->rep.info_log = (l ? l->rep : nullptr);
}

void leveldb_options_set_write_buffer_size(leveldb_options_t *opt, size_t s) {
    opt->rep.write_buffer_size = s;
}

void leveldb_options_set_max_open_files(leveldb_options_t *opt, int n) {
    opt->rep.max_open_files = n;
}

void leveldb_options_set_cache(leveldb_options_t *opt, leveldb_cache_t *c) {
    opt->rep.block_cache = c->rep;
}

void leveldb_options_set_block_size(leveldb_options_t *opt, size_t s) {
    opt->rep.block_size = s;
}

void leveldb_options_set_block_restart_interval(leveldb_options_t *opt, int n) {
    opt->rep.block_restart_interval = n;
}

void leveldb_options_set_max_file_size(leveldb_options_t *opt, size_t s) {
    opt->rep.max_file_size = s;
}

void leveldb_options_set_compression(leveldb_options_t *opt, int t) {
    opt->rep.compression = static_cast<CompressionType>(t);
}

leveldb_comparator_t *leveldb_comparator_create(
        void *state,
        void (*destructor)(void *),
        int (*compare)(
                void *,
                const char *a, size_t alen,
                const char *b, size_t blen),
        const char *(*name)(void *)) {
    leveldb_comparator_t *result = new leveldb_comparator_t;
    result->state_ = state;
    result->destructor_ = destructor;
    result->compare_ = compare;
    result->name_ = name;
    return result;
}

void leveldb_comparator_destroy(leveldb_comparator_t *cmp) {
    delete cmp;
}

leveldb_filterpolicy_t *leveldb_filterpolicy_create(
        void *state,
        void (*destructor)(void *),
        char *(*create_filter)(
                void *,
                const char *const *key_array, const size_t *key_length_array,
                int num_keys,
                size_t *filter_length),
        unsigned char (*key_may_match)(
                void *,
                const char *key, size_t length,
                const char *filter, size_t filter_length),
        const char *(*name)(void *)) {
    leveldb_filterpolicy_t *result = new leveldb_filterpolicy_t;
    result->state_ = state;
    result->destructor_ = destructor;
    result->create_ = create_filter;
    result->key_match_ = key_may_match;
    result->name_ = name;
    return result;
}

void leveldb_filterpolicy_destroy(leveldb_filterpolicy_t *filter) {
    delete filter;
}

leveldb_filterpolicy_t *leveldb_filterpolicy_create_bloom(int bits_per_key) {
    // Make a leveldb_filterpolicy_t, but override all of its methods so
    // they delegate to a NewBloomFilterPolicy() instead of user
    // supplied C functions.
    struct Wrapper : public leveldb_filterpolicy_t {
        const FilterPolicy *rep_;

        ~Wrapper() { delete rep_; }

        const char *Name() const { return rep_->Name(); }

        void CreateFilter(const Slice *keys, int n, std::string *dst) const {
            return rep_->CreateFilter(keys, n, dst);
        }

        bool KeyMayMatch(const Slice &key, const Slice &filter) const {
            return rep_->KeyMayMatch(key, filter);
        }

        static void DoNothing(void *) {}
    };
    Wrapper *wrapper = new Wrapper;
    wrapper->rep_ = NewBloomFilterPolicy(bits_per_key);
    wrapper->state_ = nullptr;
    wrapper->destructor_ = &Wrapper::DoNothing;
    return wrapper;
}

leveldb_readoptions_t *leveldb_readoptions_create() {
    return new leveldb_readoptions_t;
}

void leveldb_readoptions_destroy(leveldb_readoptions_t *opt) {
    delete opt;
}

void leveldb_readoptions_set_verify_checksums(
        leveldb_readoptions_t *opt,
        unsigned char v) {
    opt->rep.verify_checksums = v;
}

void leveldb_readoptions_set_fill_cache(
        leveldb_readoptions_t *opt, unsigned char v) {
    opt->rep.fill_cache = v;
}

void leveldb_readoptions_set_snapshot(
        leveldb_readoptions_t *opt,
        const leveldb_snapshot_t *snap) {
    opt->rep.snapshot = (snap ? snap->rep : nullptr);
}

leveldb_writeoptions_t *leveldb_writeoptions_create() {
    return new leveldb_writeoptions_t;
}

void leveldb_writeoptions_destroy(leveldb_writeoptions_t *opt) {
    delete opt;
}

void leveldb_writeoptions_set_sync(
        leveldb_writeoptions_t *opt, unsigned char v) {
    opt->rep.sync = v;
}

leveldb_cache_t *leveldb_cache_create_lru(size_t capacity) {
    leveldb_cache_t *c = new leveldb_cache_t;
    c->rep = NewLRUCache(capacity);
    return c;
}

void leveldb_cache_destroy(leveldb_cache_t *cache) {
    delete cache->rep;
    delete cache;
}

leveldb_env_t *leveldb_create_default_env() {
    leveldb_env_t *result = new leveldb_env_t;
    result->rep = Env::Default();
    result->is_default = true;
    return result;
}

void leveldb_env_destroy(leveldb_env_t *env) {
    if (!env->is_default) delete env->rep;
    delete env;
}

char *leveldb_env_get_test_directory(leveldb_env_t *env) {
    std::string result;
    if (!env->rep->GetTestDirectory(&result).ok()) {
        return nullptr;
    }

    char *buffer = static_cast<char *>(malloc(result.size() + 1));
    memcpy(buffer, result.data(), result.size());
    buffer[result.size()] = '\0';
    return buffer;
}

void leveldb_free(void *ptr) {
    free(ptr);
}

int leveldb_major_version() {
    return kMajorVersion;
}

int leveldb_minor_version() {
    return kMinorVersion;
}

}  // end extern "C"
